After a Grid Failure, the Grid is restored by creating small Islands, which are seperately powered. These Islands are then synchronised and interconnectd, with other such Islands, untill the complete Grid is restored.
What is Black Start ?
The process of creating an Islanding, during the Comlete Grid Failure. The Auxillary supply required for the Generatio is taken from the DG Sets.
What is Black Start Mock Drill?
In Black Start Mock Drill, we create a situation like the Grid failure and then charge an Island and finally Synchronising with the Grid. It is carried out at Important Generation Power Plants, to ensure fast and fluid responses of their instrumentation and controls.
Procedure for Black Start Mock Drill:
Black start Mock Drill can be divided into three parts, as follows:
1. Creation of an Island
2. Charging the Island
3.Synchronising with the Grid.
1.Creation of an Island:
- Choose a Generator ,Feeder and a Transformer, that are to be seperated from the Grid to create the Island.
- Keep that Generator and Feeder and Transformer on one Bus (Transferring all other Feeders & Generators from that Bus to other Bus) . Say, remove all the Feeders and Generators from Main Bus 2, except the selected Feeder and Generator.
- Note that the Generator Unit Breaker is on Turning Gear and its Breaker is already Off.
- Switch Off the Feeder and Transformer Breaker.
- Open the Bus Coupler Breaker, so that the selected Feeder and Generator are disconnected from the Grid.
2.Charging the Island:
- Black Start (4MW) DG Set.
- Synchronising Black Start DG Det with Selected Generation Unit.
- Generation Unit Rolling with Starting Frequenc Converter.
- Generation Unit ready for loading on Speed Controller mode.
- Charge HV Breaker of the Transformer and then LV breaker of the Transformer and then cahrge LV Feeders one by one. Thus Generation Unit is now running on Island Load Operation with Local Area Load only.
3.Synchronising with the Grid:
- Synchronize Feeder with the Generation Unit by Synchronising Relay.
- Close the Bus Coupler Breaker.